A Eukaryotic Regulatory Protein Controls Expression of a Gene A) This Protein Blocks an Activating Transcription Factor from Binding

A eukaryotic regulatory protein controls expression of a gene. Some data regarding this protein are listed in the table below. Which hypothesis about the mechanism of this protein can be ruled out? $$\begin{array} { | c | c | c | c | c | } \hline & \begin{array} { c } \text { Binding } \\\text { specificity of } \\\text { protein to DNA }\end{array} & \begin{array} { c } \text { Number of } \\\text { domains in } \\\text { protein }\end{array} & \begin{array} { c } \text { Domain } \\\text { functions }\end{array} & \begin{array} { c } \text { Effect on } \\\text { transcription }\end{array} \\\hline \begin{array} { c } \text { Regulatory } \\\text { protein X }\end{array} & \text { GGAACT } & 1 & \begin{array} { c } \text { DNA binding } \\\text { domain }\end{array} & \text { Inhibits } \\\hline\end{array}$$

A) This protein blocks an activating transcription factor from binding to the promoter.
B) This protein prevents RNA polymerase from binding to the promoter.
C) This protein competes with a transcription activator for binding to an enhancer.
D) This protein binds to Mediator proteins in the transcription initiation complex.